Enterprise workspace is quickly evolving with new networked devices to improve communication, collaboration, security, and productivity. Power over Ethernet (PoE), a way to deliver electrical power over LAN cabling to networked devices, has been widely deployed over the years to provide power to various endpoints in the enterprise workspace environment using existing conductors. In recent years, Power Over Ethernet (PoE) standards and equipment have been developed that utilize the twisted pairs to transmit DC power in addition to data. End user PoE equipment, such as telephones and video cameras, are conveniently powered through the ethernet jack, thus eliminating the need for a local AC power outlet.
PoE systems typically transmit electrical power by using one twisted pair of a datacomm cabling system containing four twisted pair communication channels to send current to equipment, and another pair to return the current to the power source. Each pair is also typically connected to ferrite core transformers (baluns) that convert the differential twisted pair signal to a single ended signal for subsequent processing. PoE current flows through the transformer windings with each wire preferably carrying half of the current. The two currents induce equal and opposite DC flux in the transformer ferrite core, resulting in cancellation and no DC flux. It is to be appreciated that any remnant DC flux can degrade the transformer's performance due to core saturation resulting in possible degradation of data transmission.
It is to be appreciated that if the two conductors in a pair have equal resistance, along with the transformer coils, a 50/50 current split is assured, and transformer saturation will not occur. However, Ohm's law dictates that a significant resistance difference will result in current imbalance and possibly core saturation. As one skilled in the art appreciates, limits have been established for maximum acceptable resistance imbalance in the data communication channel. Therefore, there is a need for qualifying a conductor for data services and to determine imbalance resistance of the conductor.